A device of the kind in question is known from DE 33 22 154. In this case, a tubular media distributor that has a slot extending in the axial direction of the tube is mounted in a two-part housing. The tube, which has a circular cross-section, is rotatably mounted in an inner cylinder which is congruent with the tube. The two housing portions respectively form two halves of the inner cylinder, a lower housing portion having a discharge slot which is flanked by two discharge lips. The lower housing portion has, in the region of the inner cylinder, a recess that extends along the edge of the discharge slot and has a tapering wedge-shaped base. By rotating the media distributor, the slot-form outlet is brought into the region of this recess. The spacing of the base of this recess depends on the rotary position of the tube. The recess forms a throttle, so that the quantity flowing through the gap may be adjusted by varying the rotary position of the tube.
DE 197 57 237 C2 describes a device in which there is a longitudinal slot in a substantially rectangular housing, the slot forming a discharge nozzle extending substantially over the entire length of the housing. A roller within the housing has a helical slot on the surface of the roller. There is a reservoir for accommodating a flowable medium between the outer wall of the roller and the inner wall of the housing and the medium may be a fluidized thermoplastic material or a molten heat-meltable adhesive. The surface of the roller is in sealing engagement against the base surface of the housing, in which there is the discharge nozzle formed by a longitudinal slot. The helical slot of the medium distributor thus crosses the discharge nozzle at a number of locations spaced apart from one another. The flowable medium may exit from the discharge nozzle at these crossing points. If the medium distributor is rotated, this exit point travels along in the direction of extent of the nozzle. By means of the rotary application head described here, threads of adhesive separated from one another may be applied to a planar workpiece surface.